You know, at that age I think both consequences and praise really need to be immediate or they don't get it. I had good luck with simply saying, "Wow! Great job brushing your teeth - now we have extra time to snuggle before bedtime." or "I like how all your toys were put away before we got to the end of the Clean Up song! You were really fast! Now we have time for a story." Basically, just showing them that their good behavior has good consequences right at that moment. Kids that age have a really hard time with delayed gratification (or punishment, for that matter). When they had bad behavior, I might say, "Oh, that's too bad that you didn't put your toys away. Now I will have to do it." (And for the record, what this means in our house is that the toys go AWAY - at that age for maybe a day, in a bag in the garage, but now that they're older, they go away FOREVER. You wouldn't believe how good they are at picking up their toys.)
As long as you reward or punish in a logical way (i.e. brushing teeth without a fuss means more time to read a story, or not picking up toys means the toys go away for a while), and right in the moment, I think you will find that your child will quickly learn what is expected and will be more likely to comply. Just my two cents!